Alternative Names
ACY2 deficiency; Aminoacylase 2 deficiency; Aspa deficiency; Aspartoacylase deficiency; Asp deficiency; Canavan-Van Bogaert-Bertrand disease; Leukodystrophy, spongiform; Spongy degeneration of central nervous system; Spongy degeneration of the brain; Spongy degeneration of white matter in infancy; Van Bogaert-Bertrand syndrome; Von Bogaert-Bertrand disease
Symptoms & Characteristics
Canavan disease is a genetic condition that causes progressive damage to nerve cells in the brain. This disease is one of a group of genetic disorders called leukodystrophies. Leukodystrophies are characterized by degeneration of myelin, which is the fatty covering that insulates nerve fibers.
The signs and symptoms of this disease usually begin in early infancy; however, the course of the condition can be quite variable. Infants with Canavan disease typically appear normal for the first few months of life. By age 3 to 5 months, affected infants begin having problems with development, including a delay in motor skills such as turning over, controlling head movement, and sitting without support. These infants typically also have poor muscle tone (called hypotonia), unusually large head size (called macrocephaly), abnormal posture, and mental retardation. Feeding and swallowing difficulties, seizures, and sleep disturbances may also develop.
The life expectancy for people with Canavan disease varies. Most affected individuals live only into childhood, although some survive into adolescence or beyond.
Treatment
There is currently no cure for Canavan disease. Lithium has demonstrated some therapeutic effects in individuals with Canavan disease. Research into other potential treatments and a cure is ongoing.
How Common Is It?
While Canavan disease occurs in people of all ethnic backgrounds, it is most common in people of Ashkenazi (eastern and central European) Jewish heritage. Studies suggest that this disorder affects 1 in 6,400 to 13,500 people in the Ashkenazi Jewish population. The incidence in other populations is unknown.
Genetics & Inheritance
Mutations in the ASPA gene cause Canavan disease.
- More than 55 mutations in the ASPA gene are known to cause Canavan disease. Two specific mutations cause most cases of the disease in people of Ashkenazi Jewish ancestry. A different mutation is most common in people who are not of Ashkenazi Jewish descent.
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Two carriers have a 25% chance with each pregnancy to have an affected child.
Genetic Testing
Clinical genetic testing for Canavan disease can be broken down into two categories: diagnostic testing and carrier testing.
- Diagnostic testing may be used to confirm or rule out a diagnosis in a person suspected to have the disorder.
- Carrier testing is typically offered after a clinical diagnosis and/or mutations have already been identified in an affected family member(s). Carrier testing is also available for people of high risk ethnic groups.
Carrier testing for the Ashkenazi-specific mutations that cause Canavan disease is available online (over the internet). This testing is available individually or as part of an Ashkenazi Jewish panel. Go to the Tests tab to link to the best providers, compare providers and read provider reviews.
Diagnostic testing and carrier testing for people who are not of Ashkenazi Jewish ancestry is available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
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